A 37-year-old with a skeletal Class III malocclusion and obstructive sleep apnoea is being planned for surgery. All of the following are appropriate for correcting a Class III skeletal relationship EXCEPT:

Correct answer: B. Le Fort I maxillary advancement performed alone

• A. Genioplasty refines chin projection and is routinely combined with jaw surgery for the aesthetic result.
• B. CORRECT as the exception in THIS patient. Maxillary advancement alone can correct mild Class III of purely maxillary origin, but this patient also has obstructive sleep apnoea, and a mandibular component to the discrepancy. Advancing only the maxilla leaves the mandibular prognathism uncorrected and fails to achieve the occlusal result. The airway consideration matters too, since mandibular setback REDUCES posterior airway space.
• C. A BSSO setback is a standard component of Class III correction where the mandible is prognathic — though it must be planned carefully in a patient with sleep apnoea.
• D. Bimaxillary surgery is the workhorse for significant Class III discrepancy: it distributes the movement between both jaws, gives a better facial result, and limits the airway compromise that a large isolated setback would cause.

Note: ⚑ The sleep apnoea is the key constraint. Maximal mandibular setback is the movement that most reduces posterior airway space and can worsen OSA. In a Class III patient WITH apnoea, planning shifts toward maximising maxillary advancement and minimising mandibular setback, or toward counterclockwise rotation of the occlusal plane. Maxillomandibular ADVANCEMENT is itself one of the most effective surgical treatments for OSA.